Computer scientist Eric Lu has developed an experimental "Ghost Font" designed to keep AI from reading text while remaining legible to humans. Instead of traditional letters, the system uses thousands of tiny moving dots that form faint characters through motion perception – a visual trick the human brain can easily recognize. In tests, leading AI models, including Claude Fable 5 and GPT-5.6 Sol, struggled to decode the hidden messages, offering a potential new way to protect human communication in the age of AI.